Unauthorized computer intrusion is known as:

The correct answer is C. hacking.

Hacking refers to the unauthorized access and intrusion into computer systems and networks. This can involve exploiting security vulnerabilities to gain access to confidential data or disrupt services. Other terms like phreaking, pharming, and phishing have different meanings: phreaking involves hacking telephone systems, pharming redirects users from legitimate websites to fraudulent ones, and phishing is a method of tricking users into revealing personal information.